Amazon Elastic MapReduce Gets Updated Hadoop, Hive and Pig Support

With this update, Amazon Elastic MapReduce users can enjoy
multiple inputs class for reading multiple types of data, and
multiple outputs class for writing multiple types of data.
Previously, customers could only run one reducer and one mapper per
job; now, ChainMapper and ChainReducer allows multiple M+RM within
one Hadoop job. Please see the announcement for more information.